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Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand

[Image: see text] Thioethers are good ligands for photoactivatable ruthenium(II) polypyridyl complexes, as they form thermally stable complexes that are prone to ligand photosubstitution. Here, we introduce a novel symmetric chelating bis(thioether) ligand scaffold, based on 1,3-bis(methylthio)-2-pr...

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Autores principales: Meijer, Michael S., Bonnet, Sylvestre
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2019
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6724527/
https://www.ncbi.nlm.nih.gov/pubmed/31433170
http://dx.doi.org/10.1021/acs.inorgchem.9b01669
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author Meijer, Michael S.
Bonnet, Sylvestre
author_facet Meijer, Michael S.
Bonnet, Sylvestre
author_sort Meijer, Michael S.
collection PubMed
description [Image: see text] Thioethers are good ligands for photoactivatable ruthenium(II) polypyridyl complexes, as they form thermally stable complexes that are prone to ligand photosubstitution. Here, we introduce a novel symmetric chelating bis(thioether) ligand scaffold, based on 1,3-bis(methylthio)-2-propanol (4) and report the synthesis and stereochemical characterization of the series of novel ruthenium(II) polypyridyl complexes [Ru(bpy)(2)(L)](PF(6))(2) ([1]–[3](PF(6))(2)), where L is ligand 4, its methyl ether, 1,3-bis(methylthio)-2-methoxypropane (5), or its carboxymethyl ether, 1,3-bis(methylthio)-2-(carboxymethoxy)propane (6). Coordination of ligands 4–6 to the bis(bipyridine)ruthenium center gives rise to 16 possible isomers, consisting of 8 possible Λ diastereoisomers and their Δ enantiomers. We found that the synthesis of [1]–[3](PF(6))(2) is diastereoselective, yielding a racemic mixture of the Λ-(S)-eq-(S)-ax-OH(eq)-[Ru](2+) and Δ-(R)-ax-(R)-eq-OH(eq)-[Ru](2+) isomers. Upon irradiation with blue light in water, [1]–[3](PF(6))(2) selectively substitute their bis(thioether) ligands for water molecules in a two-step photoreaction, ultimately producing [Ru(bpy)(2)(H(2)O)(2)](2+) as the photoproduct. The relatively stable photochemical intermediate was identified as cis-[Ru(bpy)(2)(κ(1)-L)(H(2)O)](2+) by mass spectrometry. Global fitting of the time evolution of the UV–vis absorption spectra of [1]–[3](PF(6))(2) was employed to derive the photosubstitution quantum yields (Φ(443)) for each of the two photochemical reaction steps separately, revealing very high quantum yields of 0.16–0.25 for the first step and lower values (0.0055–0.0093) for the second step of the photoreaction. The selective and efficient photochemical reaction makes the photocleavable bis(thioether) ligand scaffold reported here a promising candidate for use in e.g. ruthenium-based photo-activated chemotherapy.
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spelling pubmed-67245272019-09-05 Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand Meijer, Michael S. Bonnet, Sylvestre Inorg Chem [Image: see text] Thioethers are good ligands for photoactivatable ruthenium(II) polypyridyl complexes, as they form thermally stable complexes that are prone to ligand photosubstitution. Here, we introduce a novel symmetric chelating bis(thioether) ligand scaffold, based on 1,3-bis(methylthio)-2-propanol (4) and report the synthesis and stereochemical characterization of the series of novel ruthenium(II) polypyridyl complexes [Ru(bpy)(2)(L)](PF(6))(2) ([1]–[3](PF(6))(2)), where L is ligand 4, its methyl ether, 1,3-bis(methylthio)-2-methoxypropane (5), or its carboxymethyl ether, 1,3-bis(methylthio)-2-(carboxymethoxy)propane (6). Coordination of ligands 4–6 to the bis(bipyridine)ruthenium center gives rise to 16 possible isomers, consisting of 8 possible Λ diastereoisomers and their Δ enantiomers. We found that the synthesis of [1]–[3](PF(6))(2) is diastereoselective, yielding a racemic mixture of the Λ-(S)-eq-(S)-ax-OH(eq)-[Ru](2+) and Δ-(R)-ax-(R)-eq-OH(eq)-[Ru](2+) isomers. Upon irradiation with blue light in water, [1]–[3](PF(6))(2) selectively substitute their bis(thioether) ligands for water molecules in a two-step photoreaction, ultimately producing [Ru(bpy)(2)(H(2)O)(2)](2+) as the photoproduct. The relatively stable photochemical intermediate was identified as cis-[Ru(bpy)(2)(κ(1)-L)(H(2)O)](2+) by mass spectrometry. Global fitting of the time evolution of the UV–vis absorption spectra of [1]–[3](PF(6))(2) was employed to derive the photosubstitution quantum yields (Φ(443)) for each of the two photochemical reaction steps separately, revealing very high quantum yields of 0.16–0.25 for the first step and lower values (0.0055–0.0093) for the second step of the photoreaction. The selective and efficient photochemical reaction makes the photocleavable bis(thioether) ligand scaffold reported here a promising candidate for use in e.g. ruthenium-based photo-activated chemotherapy. American Chemical Society 2019-08-21 2019-09-03 /pmc/articles/PMC6724527/ /pubmed/31433170 http://dx.doi.org/10.1021/acs.inorgchem.9b01669 Text en Copyright © 2019 American Chemical Society This is an open access article published under a Creative Commons Non-Commercial No Derivative Works (CC-BY-NC-ND) Attribution License (http://pubs.acs.org/page/policy/authorchoice_ccbyncnd_termsofuse.html) , which permits copying and redistribution of the article, and creation of adaptations, all for non-commercial purposes.
spellingShingle Meijer, Michael S.
Bonnet, Sylvestre
Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title_full Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title_fullStr Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title_full_unstemmed Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title_short Diastereoselective Synthesis and Two-Step Photocleavage of Ruthenium Polypyridyl Complexes Bearing a Bis(thioether) Ligand
title_sort diastereoselective synthesis and two-step photocleavage of ruthenium polypyridyl complexes bearing a bis(thioether) ligand
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6724527/
https://www.ncbi.nlm.nih.gov/pubmed/31433170
http://dx.doi.org/10.1021/acs.inorgchem.9b01669
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